High hydrostatic pressure treatment of Arthrospira (Spirulina) platensis extracts and the baroprotective effect of sugars on phycobiliproteins

The effect of High Hydrostatic Pressure (HHP) (600 MPa; 300 s) upon phycobiliproteins from Spirulina platensis extract, in aqueous systems, has been investigated along with the potential baroprotective ability of several sugars (sucrose, trehalose and glucose) at different concentrations (20%, 40% w/w). Phycobiliproteins stability and technological functionality were assessed through spectroscopical and colour analysis, and radical scavenging ability. HHP treatment resulted in a decrease of the phycobiliproteins concentration with allophycocyanin being the most sensitive towards HHP stress (p ≤ 0.05). Addition of saccharides had a positive effect on phycocyanin stability with a higher residual concentration after HHP treatment (p ≤ 0.05) irrespective of the type and concentration of sugars added in the system, whilst baroprotective effects on allophycocyanin and phycoerythrin were observed only at the highest (40%) concentrations tested (p ≤ 0.05). After the HHP treatment, colouring ability of Spirulina platensis extract resulted in being directly correlated to phycocyanin concentration variation (R2 = 0.75). Addition of sugars preserved the antioxidant activity of the extract subject to high pressure regardless of the sugar type.